JPH02224581A - Screen display device - Google Patents

Abstract

PURPOSE:To convert white and black colors of a white and black display character in the lump by providing a white (black) color signal generating circuit to a video signal generating circuit, a white (black) mode circuit to a video mixer and a white black level setting register to a display control register. CONSTITUTION:In the case of displaying a character onto a display device in a white color, a white color signal from a white color signal generating circuit 180 in a video signal generating circuit 18 is outputted to a white mode circuit 173 in a video mixer 17 under the control of a white black level setting register 6a in a display control register 6. In the case of displaying a character onto the display device in a black color, a black color signal from a black color signal generating circuit 181 is outputted to a black mode circuit 175 by the register 6a. Then a white or black color signal is mixed with a display signal or the like via an external mode circuit 174 and an internal mode circuit 176 or the like in a composite video signal generating means 71 and outputted as a composite video signal to the display device and the character is displayed in white or black color. Thus, the displayed characters are converted from black into white or vice versa in the lump.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The second invention relates to a screen display device that displays characters and patterns such as channel numbers in broadcast images displayed on a display device such as a cathode ray tube. be.

[Prior Art] FIG. 3 shows an example of the configuration of a conventional screen display device of this kind. In FIG. 3, 1 is a display oscillation circuit to which the oscillation output of the π-type LC oscillation circuit 1a is supplied; 2 3 is a timing generator that generates various timings using signals oscillated by the display oscillation circuit 1, and 3 is an input terminal 3a to 3C from a microcomputer, etc. (not shown) for controlling the output of the timing generator 2 and this screen display device. 4 is a data control circuit, 5 is an address control circuit, and 7 is a display data memory for storing control data. , RAM. Reference numeral 8 denotes a display character memory for storing character patterns and the like to be displayed in the font configuration shown in FIG. 4, and is comprised of a ROM. 6 is a display control register that latches commands such as display control among the outputs of the input control circuit 3; 9 is a horizontal and vertical synchronizing signal of the image signal supplied to terminals 9a and 9b, or internally generated horizontal and vertical synchronizing signals; 11 is a display position detection circuit for detecting the display position of characters, patterns, etc. on the display device; 13 is a display control circuit; The screen display device which controls the display of the output of the display character memory 8 in accordance with the display command of the display control register 6 is composed of the above-mentioned circuits, and the output of the display control circuit 13 is connected to the video mixer. 17, and the video mixer 17 outputs the video signal via the CVIDEO terminal 17a. Further, from the display control circuit 13, R, G
, B color signals, etc. are outputted via terminals 13a to 13f. 10 is an H counter, 14 is a shift register, 15 is an oscillation circuit for generating a synchronizing signal to which the oscillation output of the oscillation element circuit 15a is supplied, 16 is a timing generator for generating a synchronizing signal, and 21 is a blinking circuit.

Next, the operation will be explained. The input control circuit 3 processes control data input from a microcomputer or the like through terminals 38 to 3c, causes a display control register 6 to latch commands such as display control, and displays character codes and the like as display contents. It is stored in the data memory 7. During display, the character code stored in the display data memory 7 accesses the display character memory 8 as output data, and the display character font output from the character memory 8 is input to the display control circuit 13. Here, the display data memory 7 is composed of (a+b) bits in total, assuming that one word is (a+b) bits and the number of characters to be displayed is C. On the other hand, it is assumed that one font of the display character memory 8 is composed of (JXm) bits, and there are n characters of such types.

Also, regarding the display timing, a synchronization signal from the image signal is input to the synchronization signal switching circuit 9, this synchronization signal is counted by the H counter 10, and the position of the displayed character is determined by the display position detection circuit 11 based on this count value. The determining 0 display control circuit 13 synchronizes the display character output with an external video signal, controls the display according to the contents of the display control register 6, outputs it, and supplies it to the video mixer 17.

Note that the synchronizing signal generation oscillation circuit 15 is the oscillation element circuit 1
5a, it is possible to generate a synchronization signal of the NTSC system or PAL system, and this switching is performed by the signal from the N/P terminal 15b, thereby outputting 4fsc or 2fsc oscillation, and the timing generator 16 for generating the synchronization signal outputs oscillation of 4fsc or 2fsc. Since a synchronizing signal is generated, display on the TV screen is possible even when there is no signal.

In addition, the video mixer 17 allows NTSC and P
It is possible to generate an AL type composite video signal and to superimpose it onto an external composite video signal. The composite video signal has character level (LECHA), external composite video input (CV I N), and blanking level (LEB).
K), background carrier color signal input (R8IN), color burst input (CBIN), and sync chip level are switched and synthesized by an analog switch and output from the CVIDEO terminal 17a. That is, the above display contents are synchronized with a composite signal generated inside the video mixer 17 as shown in FIG. 5, and the color and brightness of the display contents are set and mixed with the video signal.
Output to a TV's cathode ray tube, etc. via terminal 17a,
Data input from a microcomputer, etc. can be displayed along with images. Note that white and black are set by the potential of the luminance signal and do not require a chroma component.

[Problems to be Solved by the Invention] Conventional screen display devices are configured as described above, and when characters are displayed in black and white using superimposition, etc., one screen changes from a bright scene to a dark scene or a dark scene. When the scene changes from bright to bright, the displayed characters become difficult to see, so it is necessary to convert the character display from black to white or from white to black, but the characters must be accessed again and the display color changed for each character before output. However, since display colors cannot be converted all at once, the conversion process takes time.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a screen display device that can convert monochrome characters from white to black or from black to white all at once.

[Means for Solving the Problems] In the screen display device according to the present invention, the video signal generation circuit includes a white signal generation circuit that outputs a white signal that sets the color of the display signal to white, and a white signal generation circuit that outputs a white signal that sets the color of the display signal to white. and a black signal generation circuit that outputs a black signal to set the color to black.
The video mixer includes a white mode circuit that displays a character in white using the white signal, and a black mode circuit that displays a character in black using the black signal, and the display control register is connected to the white mode circuit or the black mode circuit that displays the character in black using the black signal. It has a black and white setting register that controls selection of the mode circuit.

[Function] The screen display device according to the present invention selects a white mode circuit using a display control register, synthesizes a white signal output from this white mode circuit and a display signal, displays a character in white, and displays a character in white first. By selecting the mode circuit, the black signal output from the white mode circuit and the display signal are combined to convert the displayed characters from white to black all at once. Furthermore, by selecting a white mode circuit when a black mode circuit is selected, the displayed characters are converted from black to white all at once.

[Example] An example of the present invention will be described below with reference to FIGS. 1 and 2. Components that are the same as those in FIGS. 3 and 4 are designated by the same reference numerals, and their explanation will be omitted.

18 is a video signal generation circuit that generates each internal video signal, and 19 is a port output control circuit that outputs various signals from port output terminals 19a to 19f. The video signal generation circuit 18 includes a white signal generation circuit 180 that outputs a white signal that sets the display character to white, and a white signal generation circuit 180 that outputs a white signal that sets the display character to black.

A black signal generation circuit 181 that outputs a black signal set to
and has. The video mixer 17 includes a chroma signal generating means 70 that mixes the internal chroma signal and the display signal, this display signal and an external video signal, and outputs the mixed signal via the COUT terminal 17b, and the composite signal or the internal luminance signal. It consists of a display signal and a composite video signal generating means 71 that mixes the display signal and an external video signal and outputs the mixed signal through the CVIDEO terminal 17a. The chroma signal generation means 70 includes an external mode circuit 170 that receives and outputs a chroma signal of a video signal from the outside via a CIN terminal 17d, and an internal mode circuit 170 that outputs an internal chroma signal generated by a chroma signal generation circuit (not shown). It consists of a mode circuit 171 and a clamp level circuit 172 that sets a clamp level. The composite video signal generating means 71 includes a white mode circuit 173 that makes a display character white in response to a white signal from the white signal generating circuit 180, and a luminance signal or a composite signal of a video signal from the outside via the CVIN terminal 17c. An external mode circuit 174 that takes in and outputs it, a black mode circuit 175 that makes the displayed character black based on the black signal from the black signal generation circuit 181, and an internal luminance signal or composite signal generation that is generated by a luminance signal generation circuit (not shown). An internal mode circuit 176 that outputs an internal composite signal generated by the circuit, and a pedestal level circuit 1 that sets a pedestal level.
77, and a sync tip level circuit 178 for setting a sync tip level. In addition, display control register 6
is connected to the white mode circuit 173 via the display control circuit 13.
or black mode circuit 175.

Next, the operation will be explained. Video mixer 17 is controlled by display control register 6. First, when displaying a character in white on a display device, white signal generation circuit 1
80 is output via the white mode circuit 173 selected by the monochrome setting register 6a, and by turning on the external mode circuit 174 etc. in the composite video signal generating means 71, the white signal is converted into a display signal. The video signal is mixed with the video signal, etc., and output as a composite video signal to a display device via the CV I DEO terminal 17a. That is, the character is displayed in white. Next, when displaying the character in black, the black signal from the black signal generation circuit 181 is outputted via the black mode circuit 175 selected by the black and white setting register 6a, and the composite video signal generation means 7
1, by turning on the internal mode circuit 176, etc., the black signal is mixed with a display signal, etc., and displayed as a composite video signal via the CVIDEO terminal 17a,
Output to device. That is, the character is displayed in black.

With the above configuration, when the screen changes from a bright scene to a dark scene and the character display must be converted from black to white, the character Display characters can be changed from black to white all at once without having to access the screen again and set the color each time. Furthermore, when the screen changes from a dark scene to a bright scene, and the character display needs to be converted from white to black, the white mode circuit 173 can be selected from the black mode circuit 175 using the black and white setting register 6a. You can convert characters from black to white in one go.

[Effects of the Invention] As described above, according to the present invention, a screen display device includes a white signal generation circuit that outputs a white signal that sets the color of the display signal to white, and a black color that sets the color of the display signal to black. A video signal generation circuit having a black signal generation circuit for outputting a signal, a white mode circuit for displaying a character display in white by the white signal, and a black mode circuit for displaying a character display in black by the black signal. Since a video mixer and a display control register having a black and white setting register for controlling the selection of the white mode circuit or the black mode circuit are provided, when converting the display character from black to white or from white to black, the character can be You can convert colors all at once without having to access it again and set the color again for each character.

[Brief explanation of the drawing]

1 and 2 are block diagrams and partial block diagrams of a screen display device that is an embodiment of the present invention, FIG. 3 is a block diagram of a conventional screen display device, and FIG. 4 shows the configuration of displayed characters. FIG. 5 is a diagram showing a composite signal. DESCRIPTION OF SYMBOLS 1... Display oscillation circuit, 2... Timing generator, 3... Input control circuit, 4... Data control circuit, 5... Address control circuit, 6... Display control register, 6a. ...Black and white setting register, 7...Display data memory, 8...Display character memory, 9...Synchronization signal switching circuit, 10...H counter, 11...Display detection circuit, 13... -Display control circuit, 17...Video mixer 18...Video signal generation circuit, 70...
Chroma signal generation means, 71... Composite video signal generation means, 173... White mode circuit, 175... Black mode circuit, 180... White signal generation circuit, 181... Black signal generation circuit.

Claims (1)

[Claims] In a screen display device that displays characters, patterns, etc. on a display device such as a cathode ray tube, there is provided an oscillation circuit that generates signals that serve as a reference for various timings, and a system that generates various signals based on the oscillation signals of the oscillation circuit. a timing generator that generates a timing signal; an input control circuit that receives and processes a control signal from an external control circuit such as a microcomputer; and a synchronization signal switching circuit that inputs a synchronization signal for a video signal to be displayed on the display device; A display position detection circuit that counts this synchronization signal to detect the display position of the display device, and control data such as characters, pattern codes, blinking information, etc. that are processed by the input control circuit and are to be displayed on the display device. a display data memory for storing the above display contents; a display character memory for storing the font of the characters displayed as the display contents;
A video signal generation circuit that generates each internal video signal for setting the color of the display signal, and a video signal generation circuit that generates each internal video signal to set the color of the display signal, and each mode circuit that displays the display content at a predetermined position of the display device using the position detection signal from the display position detection circuit. a video mixer that mixes a predetermined display signal of the display signal into the video signal; and a display control register that holds data that is input from the external control circuit to the input control circuit, and the video signal generation circuit includes The video mixer includes a white signal generation circuit that outputs a white signal that sets the color of the signal to white, and a black signal generation circuit that outputs a black signal that sets the color of the display signal to black. The display control register includes a white mode circuit that displays a character in white in response to a signal, and a black mode circuit that displays a character in black in response to the black signal, and the display control register controls selection of the white mode circuit or the black mode circuit. 1. A screen display device characterized by having a black and white setting register for performing.